High purity copper sulfate and method for production thereof

Abstract

Provided are high purity copper sulfate wherein the content of Ag impurities is 1 wtppm or less, and having a purity of 99.99 wt % or higher, and a manufacturing method of high purity copper sulfate including the steps of dissolving crude copper sulfate crystals or copper metal, and subjecting this to active carbon treatment or solvent extraction and active carbon treatment in order to realize recrystallization. The present invention aims to provide a manufacturing method of high purity copper sulfate capable of efficiently removing impurities at a low cost by dissolving commercially available copper sulfate crystals in purified water or acid and thereafter subjecting this to the refining process, and high purity copper sulfate obtained thereby.

1. A copper sulfate comprising a high purity copper sulfate having a purity of 99.99 wt % or higher and contents of Ag impurities of less than 0.01 wtppm, metalloid element impurities of As, Sb, and Bi of less than 0.1 wtppm, respectively, radioactive elements of U and Th of less than 0.001 wtppm, respectively, and heavy metal elements of Fe, Cr, and Ni of less than 0.1 wtppm, respectively. 
     
     
       2. A copper sulfate according to  claim 1 , wherein organic and foreign matter impurities are contained at a level such that, when said copper sulfate is dissolved in water, undissolved residue of 1 μm or greater exists in an amount of 100 residues/L or less. 
     
     
       3. A copper sulfate according  claim 2 , wherein said high purity copper sulfate has a purity of 99.999 wt % or higher. 
     
     
       4. A copper sulfate according  claim 1 , wherein said high purity copper sulfate has a purity of 99.999 wt % or higher. 
     
     
       5. A method of manufacturing high purity copper sulfate comprising the steps of dissolving copper sulfate having a purity of 95 to 99.5 wt %, and subjecting this to active carbon treatment and solvent extraction to realize recrystallization and to produce a high purity copper sulfate having a purity of 99.99 wt % or higher and contents of Ag impurities of less than 0.01 wtppm, metalloid element impurities of As, Sb, and Bi of less than 0.1 wtppm, respectively, radioactive elements of U and Th of less than 0.001 wtppm, respectively, and heavy metal elements of Fe, Cr, and Ni of less than 0.1 wtppm, respectively. 
     
     
       6. A method according to  claim 5 , wherein organic and foreign matter impurities are reduced to a level such that, when said high purity copper sulfate is dissolved in water, undissolved residue of 1 μm or greater exists in an amount of 100 residues/L or less. 
     
     
       7. A method according  claim 6 , wherein said high purity copper sulfate has a purity of 99.999 wt % or higher. 
     
     
       8. A method according  claim 5 , wherein said high purity copper sulfate has a purity of 99.999 wt % or higher. 
     
     
       9. A method of manufacturing high purity copper sulfate, comprising the steps of:
 dissolving copper sulfate crystals or copper metal raw material having a purity of 95 to 99.9 wt % in purified water or acid at room temperature to form a solution; 
 subjecting said solution to solvent extraction and active carbon treatment; 
 after said solvent extraction and active carbon treatment, filtering said solution, heating the filtrate to a temperature of 50 to 100° C., and performing evaporative concentration thereto; 
 after said filtering, heating and evaporative concentration, cooling said filtrate to room temperature to deposit high purity copper sulfate crystals of blue color having a purity of 99.99 wt % or higher and contents of Ag impurities of less than 0.01 wtppm, metalloid element impurities of As, Sb, and Bi of less than 0.1 wtppm, respectively, radioactive elements of U and Th of less than 0.001 wtppm, respectively, and heavy metal elements of Fe, Cr, and Ni of less than 0.1 wtppm, respectively. 
 
     
     
       10. A method according to  claim 9 , wherein during said dissolving step, the purified water or acid is diluted sulfuric acid. 
     
     
       11. A method according to  claim 10 , wherein, during said dissolving step, the copper sulfate crystals or copper metal raw material is copper sulfate crystals (Cu 2 SO 4 .5H 2 O) having a purity of 95 to 99.9 wt %. 
     
     
       12. A method according to  claim 9 , wherein the solvent extraction is performed with D2EHPA. 
     
     
       13. A method according to  claim 9 , wherein, during said cooling step, the depositing of high purity copper sulfate crystals is terminated such that a residual liquid containing non-recrystallized copper sulfate remains. 
     
     
       14. A method according to  claim 13 , wherein the residual liquid is 2 to 40 wt % of an original fluid volume of the filtrate. 
     
     
       15. A method according to  claim 13 , further comprising the steps of removing the high purity copper sulfate crystals from the residual liquid and drying the high purity copper sulfate crystals at a drying temperature of 40 to 100° C.